DOCTORS STRETCH RULES ON AIDS DRUG

By GINA KOLATA

Published: December 21, 1987

Defying official recommendations, a growing number of doctors who treat carriers of the AIDS virus are prescribing a powerful, potentially toxic drug even before the patients develop serious signs of disease.

The drug is azidothymidine, or AZT, which is licensed by the Food and Drug Administration only for certain patients with AIDS itself or who show some disease symptoms and whose immune systems are seriously damaged, groups in which the benefits of AZT have been established. But once a drug is approved, doctors may legally prescribe it to any patient.

Every one of more than a dozen AIDS physicians and health authorities interviewed said prescribing AZT to patients without symptoms had become a widespread practice as the drug, once scarce, became readily available. Doctors Split on Usage

The practice has split the medical community. Some doctors supported it as a compassionate response to an unusual threat. Others were deeply alarmed, saying they could not recall when a drug with such toxic potential had been so widely prescribed for a condition other than those specified by the Food and Drug Administration.

''I don't think there was ever before a situation like this in medicine,'' said Dr. Itzhak Brook of the Uniformed Services University of the Health Sciences in Bethesda, Md., who was chairman of an F.D.A advisory committee that evaluated AZT. ''This is just what I was afraid of.''

Experts who, like Dr. Brook, are worried about the trend say that for relatively healthy patients there is no proof that AZT will provide benefits that outweigh the substantial risks. Those risks include the suppression of bone marrow, which can cause severe anemia and make patients vulnerable to life-threatening infections. Fear Moves Doctor and Patient

But even the staunchest critics are sympathetic to the plight of frightened patients and their doctors. Some of these doctors find it impossible to refrain from using the drug, knowing that it may be only a matter of time until the patient's immune system falters still more and he develops the fatal symptoms of acquired immune deficiency syndrome.

''I'm very wary'' of giving the drug to healthy AIDS virus carriers, said Dr. Jeffrey Laurence of the Cornell University School of Medicine.''But there are a lot of scared people out there.''

Dr. William Siroty, a New York City doctor who treats patients with AIDS, said he gave AZT to healthy virus carriers when they wanted it. Many patients who know they are infected with the AIDS virus ''feel better knowing they're doing something about it,'' he said.

Mounting evidence, experts say, indicates that a substantial number, probably a majority, of people infected with the AIDS virus will eventually develop AIDS. But many people have carried the virus for years without serious ill effects. Some doctors worry that premature use of AZT will deprive such patients of healthy years without providing any sure benefits. Use of Unproved Drugs

In addition to AZT, worried carriers of the virus are taking various unproved drugs, many of which experts said were probably harmless. But some experts are concerned that these alternative treatments may harm the patients.

The aggressive treatment also reflects a dismay among those active in the drive against AIDS and some doctors over what they regard as the slow pace of Government-sponsored research.

Others say that sound studies necessarily take time. They add that no useful scientific information will result from the wide dispensing of the drug since no data are being gathered.

''The best thing to do now is to let the scientific community work this out,'' said Dr. Samuel Broder of the National Cancer Institute, who played a key role in the development of AZT.

AZT is the only drug on the market for the treatment of AIDS. Although it does not cure AIDS, it does extend the lives of some AIDS patients. The Federal Government is starting studies to see if the drug helps patients who are less ill than the original study group, but officials said it would be years before answers were in. #10,000 in U.S. Take AZT The manufacturer, the Burroughs Wellcome Company, said that more than 10,000 Americans were taking AZT but that it had no precise figures, nor any record of how many met the guidelines for its use. Nationally, no one keeps data even on the number of patients who would theoretically meet the guidelines, or what proportion of them are taking the drug.

In addition to AZT's dangerous side effects, another drawback of the drug is its expense. AZT has cost many patients as much as $10,000 a year, although doctors said that most insurance companies were not balking at paying for it even when the patients were not seriously ill. Last week, Burroughs Wellcome reduced the wholesale price of AZT by 20 percent, but the cost will still be high.

Some doctors assert there is reason to believe that AZT can help patients who have not yet become ill and that its side effects may be less severe for them. ''It is believed, but not proven, that the drug is much easier to tolerate when you're healthy,'' said Dr. Michael Greico, chief of infectious diseases at St. Luke's-Roosevelt Hospital in New York City. ''We don't know if it will retard the development of the disease, but it is likely that it will,'' he added. T Cells Used as a Barometer

Doctors who are giving AZT to healthier patients emphasize that they are not prescribing it blindly. Instead, they are monitoring the patients' immune cells and are suggesting use of the drug only when they believe the patient's T-4 cells, immune system cells that the AIDS virus attacks, are dropping dangerously low.

This leads them into what some say is the shaky science of T-cell numerology. A normal T-4 cell count is 800 to 1,000 cells per cubic centimeter of blood. As an AIDS infection progresses, the number of T-4 cells drop. But experts disagree on exactly what the numbers mean.

Everyone agrees that a patient with a T-4 cell count of less than 200 has a seriously crippled immune system. But a low T-4 cell count does not always mean imminent AIDS. ''I've followed patients who had T-4 cell counts of less than 10 for a year, and nothing happened to them,'' said Dr. Douglas Dieterich of New York University Medical Center. Where to Draw the Line

Some of the doctors offering AZT to healthier patients do so when their T-4 cell counts have dropped to 200, even if no disease symptoms are present. Others offer it to anyone whose T-4 cell count is dropping rapidly, others suggest it to those whose count is less than 300, others use 400 to 500 as a cut-off, and still others have no set guidelines but let the patients decide if they want the drug.

Dr. Jack Weissman, a New York City physician who has several hundred patients who are infected with the AIDS virus, explained why some doctors, including himself, were defying the AZT guidelines and prescribing unproved new drugs.

''I know you don't get better by yourself,'' he said. ''If I see that your T cells are dropping by 50 points a month, I can wait until you-know-what hits the fan. Or I can anticipate and try and head off what I think is a certainty.''

Dr. Weissman added that with AZT in particular, patients whose T-4 cell count was dropping must ask themselves, ''Do you want to wait until you qualify for the drug?'' After all, he said, ''sooner or later you're going to qualify, no question about it.''